tetra- Look up tetra- at Dictionary.com
before vowels tet-, word-forming element meaning "four," from Greek tetra-, combining form of tettares (Attic), tessares "the numeral four" (see four).
tetracycline (n.) Look up tetracycline at Dictionary.com
1952, with chemical suffix -ine (2) + tetracyclic "containing four fused hydrocarbon rings," from tetra- + cyclic (see cycle (n.)).
tetrad (n.) Look up tetrad at Dictionary.com
"the number four, collection of four things," 1650s, from Greek tetras (comb. form tetrad-) "group of four, number four" (see tetra-).
tetragrammaton (n.) Look up tetragrammaton at Dictionary.com
c.1400, from Greek (to) tetragrammaton "(the word) of four letters," from tetra- "four" (see four) + gramma (genitive grammatos) "letter, something written" (see grammar). The Hebrew divine name, transliterated as YHWH, usually vocalized in English as "Jehovah" or "Yahweh."
tetrahedron (n.) Look up tetrahedron at Dictionary.com
"triangular pyramid, solid figure contained by four triangular surfaces," 1560s, from Late Greek tetraedron, noun use of neuter of tetraedros (adj.) "four-sided," from tetra- "four" (see tetra-) + hedra "seat, base, chair, face of a geometric solid," from PIE root *sed- (1) "to sit" (see sedentary). Related: Tetrahedral.
tetralogy (n.) Look up tetralogy at Dictionary.com
1650s, from Greek tetralogia, from tetra- (see tetra-) + -logia (see -logy). A group of four dramatic compositions, originally three tragedies (the trilogia) and a Satyric play.
tetrameter (n.) Look up tetrameter at Dictionary.com
1610s, from Late Latin tetrametrus, from Greek tetrametron "verse of four measures" (generally trochaic), noun use of neuter of tetrametros (adj.) "having four measures," from tetra- "four" (see tetra-) + metron "measure" (see meter (n.2)).
tetrapod (n.) Look up tetrapod at Dictionary.com
"four-footed animal, quadruped," 1826, from Modern Latin tetrapodus, from Greek tetrapous "four-footed," as a noun, "four-footed animal," from tetra- (see tetra-) + pous (see foot n.)).
tetrarch (n.) Look up tetrarch at Dictionary.com
late Old English tetrarche "ruler of one of four divisions of a kingdom or province," from Late Latin tetrarcha, from tetrarches, from Greek tetrarkhes "leader of four companies, ruler of four provinces," from tetra- "four" (see tetra-) + arkhein "to rule" (see archon). Applied generally to subordinate rulers in the Roman Empire, especially in Syria. Related: Tetrarchy.
tetter (n.) Look up tetter at Dictionary.com
skin disease, Old English teter, from a reduplicated form of PIE *der- (2) "to split, peel, flay" (see tear (v.1)).
Teuton (n.) Look up Teuton at Dictionary.com
"a German," 1833, in modern use often in contrast to Celt, probably a back-formation from Teutonic.
Teutonic (adj.) Look up Teutonic at Dictionary.com
1610s, "of or pertaining to the Germanic languages and to peoples or tribes who speak or spoke them," from Latin Teutonicus, from Teutones, Teutoni, name of a tribe that inhabited coastal Germany near the mouth of the Elbe and devastated Gaul 113-101 B.C.E., probably via Celtic from Proto-Germanic *theudanoz, from PIE *teuta-, the common word for "people, tribe" (cognates: Lithuanian tauto, Oscan touto, Old Irish tuath, Gothic þiuda, Old English þeod "people, race, nation").

Used in English in anthropology to avoid the modern political association of German; but in this anthropoligical sense French uses germanique and German uses germanisch, because neither uses its form of German for the narrower national meaning (compare French allemand, for which see Alemanni; and German deutsch, under Dutch).

The Teutonic Knights (founded c.1191) were a military order of German knights formed for service in the Holy Land, but who later crusaded in then-pagan Prussia and Lithuania. The Teutonic cross (1882) was the badge of the order.
Tex Look up Tex at Dictionary.com
nickname for a Texan, by 1903, from Texas.
Tex-Mex (adj.) Look up Tex-Mex at Dictionary.com
by 1914, from Texas + Mexico. An earlier noun for "Texan of Mexican background" was Texican (1863).
Texas Look up Texas at Dictionary.com
Mexican province, briefly an independent nation and now a U.S. state, from Spanish Texas, Tejas, earlier pronounced "ta-shas," originally an ethnic name, from Caddo (eastern Texas Indian tribe) taysha "friends, allies," written by the Spanish as a plural. Related: Texan. Baseball Texas-leaguer "ball popped up just over the head of the infielders and falling too close for outfielders to catch" is recorded from 1905, named for the minor league that operated in Texas from 1902 (one theory is that outfielders played unusually deep in Texas because hit balls bounced hard off the hard, sun-baked ground).
text (n.) Look up text at Dictionary.com
late 14c., "wording of anything written," from Old French texte, Old North French tixte "text, book; Gospels" (12c.), from Medieval Latin textus "the Scriptures, text, treatise," in Late Latin "written account, content, characters used in a document," from Latin textus "style or texture of a work," literally "thing woven," from past participle stem of texere "to weave, to join, fit together, braid, interweave, construct, fabricate, build," from PIE root *teks- "to weave, to fabricate, to make; make wicker or wattle framework" (see texture (n.)).
An ancient metaphor: thought is a thread, and the raconteur is a spinner of yarns -- but the true storyteller, the poet, is a weaver. The scribes made this old and audible abstraction into a new and visible fact. After long practice, their work took on such an even, flexible texture that they called the written page a textus, which means cloth. [Robert Bringhurst, "The Elements of Typographic Style"]
text (v.) Look up text at Dictionary.com
"to send a text message by mobile system," 2005; see text (n.). Related: Texted; texting. Formerly it meant "to write in text letters" (1590s), text letters being a kind of large writing used by clerks in the text or body of a manuscript (distinguished from the smaller hand used in the notes).
textbook (n.) Look up textbook at Dictionary.com
also text-book, "book used by students," 1779, from text (n.) + book (n.). Earlier (1730) it meant "book printed with wide spaces between the lines" for notes or translation (such a book would have been used by students), from the notion of the text of a book being more open than the close notes. As an adjective from 1916.
textile (n.) Look up textile at Dictionary.com
1620s, from Latin textilis "a web, canvas, woven fabric, cloth, something woven," noun use of textilis "woven, wrought," from texere "to weave," from PIE root *teks- "to make" (see texture (n.)). As an adjective from 1650s.
textual (adj.) Look up textual at Dictionary.com
late 14c., textuel "of or pertaining to text," also "well-read," from Old French textuel, from Latin textus (see text). English spelling conformed to Latin from late 15c. Related: Textually.
texture (n.) Look up texture at Dictionary.com
early 15c., "network, structure," from Middle French texture and directly from Latin textura "web, texture, structure," from stem of texere "to weave," from PIE root *teks- "to weave, to fabricate, to make; make wicker or wattle framework" (cognates: Sanskrit taksati "he fashions, constructs," taksan "carpenter;" Avestan taša "ax, hatchet," thwaxš- "be busy;" Old Persian taxš- "be active;" Latin tela "web, net, warp of a fabric;" Greek tekton "carpenter," tekhne "art;" Old Church Slavonic tesla "ax, hatchet;" Lithuanian tasau "to carve;" Old Irish tal "cooper's ax;" Old High German dahs, German Dachs "badger," literally "builder;" Hittite taksh- "to join, unite, build"). Meaning "structural character" is recorded from 1650s. Related: Textural.
texture (v.) Look up texture at Dictionary.com
1888 (implied in textured), "to give a texture to, to make not smooth or plain," from texture (n.).
TGIF Look up TGIF at Dictionary.com
also T.G.I.F., by 1946, slang abbreviation of "Thank God (or "goodness"), it's Friday" (end of the work week).
th Look up th at Dictionary.com
A sound found chiefly in words of Old English, Old Norse or Greek origin, unpronounceable by Normans and many other Europeans. In Greek, the sound corresponds etymologically to Sanskrit -dh- and English -d-; and it was represented graphically by -TH- and at first pronounced as a true aspirate (as still in English outhouse, shithead, etc.). But by 2c. B.C.E. the Greek letter theta was in universal use and had the modern "-th-" sound. Latin had neither the letter nor the sound, however, and the Romans represented Greek theta by -TH-, which they generally pronounced, at least in Late Latin, as simple "-t-" (passed down to Romanic languages, as in Spanish termal "thermal," teoria "theory," teatro "theater").

In Germanic languages it represents PIE *-t- and was common at the start of words or after stressed vowels. To represent it, Old English and Old Norse used the characters ð "eth" (a modified form of -d-) and þ "thorn," which originally was a rune. Old English, unlike Old Norse, seems never to have standardized which of the two versions of the sound ("hard" and "soft") was represented by which of the two letters.

The digraph -th- sometimes appears in early Old English, on the Roman model, and it returned in Middle English with the French scribes, driving out eth by c.1250, but thorn persisted, especially in demonstratives (þat, þe, þis, etc.), even as other words were being spelled with -th-. The advent of printing dealt its death-blow, however, as types were imported from continental founders, who had no thorn. For a time y was used in its place (especially in Scotland), because it had a similar shape, hence ye for the in historical tourist trap Ye Olde _______ Shoppe (it never was pronounced "ye," only spelled that way).

The awareness that some Latin words in t- were from Greek th- encouraged over-correction in English and created unetymological forms such as Thames and author, while some words borrowed from Romanic languages preserve, on the Roman model, the Greek -th- spelling but the simple Latin "t" pronunciation (as in Thomas and thyme).
Thaddeus Look up Thaddeus at Dictionary.com
masc. proper name, from Latin Thaddaeus, from Greek Thaddaios, from Talmudic Hebrew Tadday. Klein derives this from Aramaic tedhayya (pl.) "breasts." Thayer's "Greek-English Lexicon of the New Testament" suggests the sense might be "large-hearted," hence "courageous." In the Bible, a surname of the apostle Jude, brother of James the Less.
Thai Look up Thai at Dictionary.com
1808, native name, Tai, literally "free."
Thailand Look up Thailand at Dictionary.com
from Thai, indigenous name of the inhabitants, + land (n.). Also see Siam.
thalamus (n.) Look up thalamus at Dictionary.com
plural thalami, 1753, "the receptacle of a flower," Modern Latin, from Latin thalamus "inner chamber, sleeping room" (hence, figuratively, "marriage, wedlock"), from Greek thalamos "inner chamber, bedroom," related to thalame "den, lair," tholos "vault, vaulted building." Used in English since 1756 of a part of the forebrain where a nerve appears to originate.
thalassemia (n.) Look up thalassemia at Dictionary.com
from thalasso- "sea" + haima "blood" (see -emia).
thalasso- Look up thalasso- at Dictionary.com
before vowels thalass-, word-forming element meaning "sea, the sea," from comb. form of Greek thalassa "the sea" (in Homer, when used of a particular sea, "the Mediterranean," as opposed to okeanos), a word from a lost pre-Greek Mediterranean language. In Attic Greek thalatta, hence sometimes thalatto-.
thaler (n.) Look up thaler at Dictionary.com
old German silver coin; see dollar.
Thalia Look up Thalia at Dictionary.com
fem. proper name, from Latinized form of Greek Thaleia, "the joyful Muse," presiding over comedy and idyllic poetry, literally "the blooming one," fem. proper name from adjective meaning "blooming, luxuriant, bounteous," from thallein "to bloom," related to thalia "abundance," thallos "young shoot" (see thallus). Also the name of one of the three Graces, patroness of festive meetings.
Thalidomide (n.) Look up Thalidomide at Dictionary.com
1958, from "phthalimidoglutarimide," based on abbreviated form of naphthalene; a morning-sickness drug responsible for severe birth defects in Europe from 1956 to 1961, when it was withdrawn. It never was approved for use in America thanks to the efforts of Dr. Helen Brooke Taussig (1898-1986). Thalidomide baby is attested from 1962.
thallium (n.) Look up thallium at Dictionary.com
rare metallic element, 1861, Modern Latin, from Greek thallos "young shoot, green branch" (see thallus) + element name ending -ium. So called by its discoverer, Sir William Crookes (1832-1919), from the green line in its spectrum by which he detected it. Related: Thallic.
thallus (n.) Look up thallus at Dictionary.com
1829, Latin, from Greek thallos "green shoot, young branch, twig," related to thalia "abundance," thalos "scion, child," ultimately from PIE root *dhal- "to bloom" (cognates: Armenian dalar "green, fresh," Albanian dal' "I sprout," Old Irish duilesc, a type of algae).
thalweg (n.) Look up thalweg at Dictionary.com
1831, from German Thalweg "path along the bottom of a valley," from thal (see dale) + weg (see way).
Thames Look up Thames at Dictionary.com
river through London, Old English Temese, from Latin Tamesis (51 B.C.E.), from British Tamesa, an ancient Celtic river name perhaps meaning "the dark one." The -h- is unetymological (see th).
Thammuz (n.) Look up Thammuz at Dictionary.com
1530s, from Hebrew tammuz, tenth month of the Jewish civil year, fourth of the sacred, covering parts of June and July; also the name of a Syrian deity equivalent to Phoenician Adon, whose festival began with the new moon of this month (compare Tammuz).
than (conj.) Look up than at Dictionary.com
Old English þan, conjunctive particle used after a comparative adjective or adverb, from þanne, þænne, þonne "then" (see then). Developed from the adverb then, and not distinguished from it by spelling until c.1700.

The earliest use is in West Germanic comparative forms introducing the second member, i.e. bigger than (compare Dutch dan, German denn), which suggests a semantic development from the demonstrative sense of then: A is bigger than B, evolving from A is bigger, then ("after that") B. Or the word may trace to Old English þonne "when, when as," such as "When as" B is big, A is more (so).
thanage (n.) Look up thanage at Dictionary.com
c.1400, from Anglo-French thaynage (c.1300), from English thane + Old French suffix -age (see -age).
thanatism (n.) Look up thanatism at Dictionary.com
belief that at death the soul ceases to exist, 1900, from thanato- + -ism.
thanato- Look up thanato- at Dictionary.com
before vowels thanat-, word-forming element meaning "death," from Greek thanatos "death," from PIE *dhwene- "to disappear, die," perhaps from a root meaning "dark, cloudy" (compare Sanskrit dhvantah "dark"). Hence Bryant's "Thanatopsis", with Greek opsis "a sight, view."
thanatology (n.) Look up thanatology at Dictionary.com
"scientific study of death," 1837, from thanato- "death" + -logy. In 1970s, some undertakers made a bid to be called thanatologists; but from 1974 that word has been used principally in reference to specialists in the needs of the terminally ill.
thanatos (n.) Look up thanatos at Dictionary.com
"death instinct," 1935, in Freudian psychology, from Greek thanatos "death" (see thanato-).
thane (n.) Look up thane at Dictionary.com
Old English þegn "military follower, one who holds lands in exchange for military service," also "vassal, retainer, attendant," from Proto-Germanic *thegnas (cognates: Old Saxon thegan "follower, warrior, boy," Old Norse þegn "thane, freeman," Old High German thegan, German Degen "thane, warrior, hero"), from PIE *tek-no- (cognates: Sanskrit takman "descendant, child," Greek teknon "child"), from root *tek- "to beget, give birth to" (cognates: Greek tekos "child, the young of animals," tokos "childbirth, offspring, produce of money, interest"). Also used in Old English for "disciple of Christ." Specific sense of "man who ranks between an earl and a freeman" is late 15c.

The modern spelling is from Scottish, where early 13c. it came to mean "chief of a clan, king's baron," and it has predominated in English probably due to the influence of "Macbeth;" normal orthographic changes from Old English ðegn would have produced Modern English *thain. Some historians now use thegn to distinguish Anglo-Saxon thanes from Scottish thanes.
thang (n.) Look up thang at Dictionary.com
by 1937, representing in print a Southern U.S. pronunciation thing.
thank (v.) Look up thank at Dictionary.com
Old English þancian, þoncian "to give thanks, thank, to recompense, reward," from Proto-Germanic *thankojan (cognates: Old Saxon thancon, Old Norse þakka, Danish takke, Old Frisian thankia, Old High German danchon, Middle Dutch, Dutch, German danken "to thank"), from *thankoz "thought, gratitude," from PIE root *tong- "to think, feel."

Related phonetically to think as song is to sing; for sense evolution, compare Old High German minna "loving memory," originally "memory." Related to Old English noun þanc, þonc, originally "thought," but by c.1000 "good thoughts, gratitude." In ironical use, "to blame," from 1550s. To thank (someone) for nothing is recorded from 1703. Related: Thanked; thanking.
thank you Look up thank you at Dictionary.com
polite formula used in acknowledging a favor, c.1400, short for I thank you (see thank). As a noun, from 1792.
thankful (adj.) Look up thankful at Dictionary.com
Old English þancful "satisfied, grateful," also "thoughtful, ingenious, clever;" see thank + -ful. Related: Thankfully; thankfulness. Thankfully in the sense "thankful to say" is attested by 1966, but deplored by purists (compare hopefully).
thankless (adj.) Look up thankless at Dictionary.com
"likely to not be rewarded with thanks," 1540s, from thank + -less. Related: Thanklessly; thanklessness.